This application claims priority based on Japanese application number 2001-253516, filed Aug. 23, 2001.
The present invention relates to a belt-like corset for use in the treatment of low back pain (hereinafter xe2x80x9cLBPxe2x80x9d).
Low back pain affects more than 60% of the United States adult population at some time during their lives. Each year in the United States billions of dollars are lost in wages and direct medical costs for low back pain. Consequently, lumbar back belts have gained popularity in many industries under the assumption that their use will reduce low back injuries and thereby decrease medical costs. Majkowski G R et al, 23(19) SPINE 2104-9, 2104 (1998)
Conservatively, low back pain is treated with joint manipulation, myofascial therapy, a combination of both, or xe2x80x9cback school.xe2x80x9d Back school is a program that teaches patients the recommended sitting and standing neutral postures, body mechanics, and exercises. In a randomized, assessor-blinded clinical trial of 206 patients, the only significant difference between these treatments after three weeks was a higher pain score with myofascial therapy alone compared with combined therapy. Back school was shown to be as effective as the other procedures. Hsieh, C j et al, 27(11) SPINE 1142-8 (2002).
Low back pain may be associated with disc herniation, disc degeneration and segmental instability and has been treated with gravitational traction by suspending the patient in a hanging, upright position to widen the intervertebral space. It is associated with increased lordosis that is measured by Ferguson""s angle, the angle between the base of the sacrum and the horizontal. Harrison D D et al, 11(5) J Spinal Disorders 430-439, 434 (1998). In a study on the effect of suspension traction, both patients and controls showed a significant increase in Ferguson""s angle during traction and an increase in the distance between L1 and S1. Tekeoglue I, et al 23(9) SPINE 1061-1064 (1998).
Exactly why people with low back pain benefit from wearing a lumbar corset remains unclear, but restriction of motion, decreased disc pressure and changes in posture are most often cited, Thoumie P, et al, 13(1) CLIN BIOMECH 18-26, 19 (1998). One concept of back supports is to increase intra-abdominal pressure to produce a rigid tube effect that promotes decompression and posterior vectors, both of which should aid in the decompression of the spine and decrease the load on the extensors. Ciriello V M and Snook, S H J, 20(11) SPINE 1271-1278 (1995). Other groups report that the corset is of no benefit and should never be prescribed unless a patient has already used it successfully. Helliwell P S and Wright V, 30(1) BR J RHEUMATOL 62 (1991). When the Freeman Lumbosacral Corset was compared with the conservative treatments of spinal manipulation, transcutaneous muscle stimulation and massage in patients with subacute low back pain, no significant differences were observed. Pope M H, et al, 19(22) SPINE 2571-7, 2576 (1994).
A conventional corset is comprised of a belt that is stretchable in its longitudinal direction and is applied to the waist portion and wrapped around the body in a state of resisting the contractile force produced when the corset is expanded and specifically, at the abdomen. The the longitudinal ends of the expansion belt member are attached to each other by attachable and detachable means of a face fastener or the like. Thereby, the body is strongly fastened to achieve prevention, alleviation or treatment of low back pain.
Various improvements have been offered. U.S. Pat. No. 4,559,933, to Batard, teaches an orthopaedic lumbo-sacral corset of a plastic material shell which is adaptable to a widened range of corpulencies and is connected along its adjacent dorsal edges by a semi-rigid thin band forming a hinge adapted to be generally aligned with the spine of the wearer so as more clearly to orient the shells, with attachment and tightening structure between the adjacent front edges of the two half-shells and an inflatable lumbar pad forming two symmetrical pads relative to the axis. U.S. Pat. No. 5,634,891, to Beczak teaches a complex arrangement to be wrapped around the torso of a human body and cause an increase in intra-abdominal pressure and a relief in pain associated with disorders of the spinal column. It is comprised of back and front panels held together by expandable straps. U.S. Pat. No. 4,622,957, to Curlee, teaches a therapeutic corset appliance which consists of an elongated rigid or semi-rigid support surface and a flexible bladder disposed on the support surface possessing a low coefficient of stretchability.
The need to restore and maintain the lumbar lordosis has been recognized at least since Hippocrates, at about 400 BC, recommended pressing sharply on the kyphosis of a patient with lumbar pain. McKenzi R A, 89 NZ MED J 22-23 (1979). Prolonged sitting, as in an office, is generally accepted as a high risk factor for low back pain and may decrease lordosis of the lumbar spine. Lengsfeld M, et al, 22 MED ENG PHYSICS 665-9 (2000). The postural benefit of sitting with a lumbar support pillow documents the need to correct lordosis in patients with LBP. Majeske C and Buchanan C, 64 (10) PHYS THER 1531-5 (1984). In contrast, Williams advocated conservative treatment for low back pain based on reducing the lumbosacral angle and recommended that the spine be maintained in flexion when changing position. Williams P C, 5 CLIN ORTHOP 28-40 (1955).
Lumbar lordosis is strongly correlated with sacral inclination in both controls and patients with low back pain (LBP) and was greater in controls, particularly in the sixth decade of life (p less than 0.001). Increased thoracic kyphosis was seen more in LBP than in controls and the difference was significant after the sixth decade. (p less than 0.01). The importance of intraoperative positioning for maintenance of physiological lumbar lordosis in patients undergoing instrumented lumbar fusions has been the subject of clinical research. Korovessis P, Stamatakis M, and Baikousis A, 12(2) JL SPINAL DISORD 131-137 (1999). The maximal difference between the lowermost and highest values of lumbar lordosis was significantly greater in the controls (p less than 0.001). In the controls, the distal (L4-L5) lordosis increased considerably with increasing age. LBP patients, however, showed only a slight increase in the distal lumbar lordosis with age. Based on these observations, chronic LBP patients appear to lose their ability to compensate for the increased thoracic kyphois, and have a more relative hypolordotic lumbar spine than controls. Korovessis, Id. However, other authors have reported that there are no statistically significant differences between patients with acute or chronic pain and normals in thoracic kyphosis or lumbar lordosis. Tuzin et al, 18 CLIN RHEUMATOL 308-312, 311 (1990).
Lumbosacral back belts for back support have been marketed as a significant aid in the prevention of low back pain. Lumbosacral belts have been used in weight lifting by athletes and have been demonstrated to restrict standing flexion, Lantz, S A and Schultz A B 11(8) Spine 834-7, 835 (1996), and improve abdominal muscle strength and lifting capacity in healthy women. Smith E B et al, 21(3) SPINE 356-366 (1996). Researchers have indirectly calculated compressive forces to the spine and concluded that lumbar supports decreased forces affecting the spine. Smith, Id., at 357. Sixty-nine (69) healthy women aged 20 to 40 were studied in a cross-over design, each subject lifting with and without a lumbosacral belt. Of these, 36 were capable of lifting more weight with the belt, 5 lifted less, and there was no change in 28 of the subjects (p less than 0.0001). At 362-3. Other groups, however, found no significant differences in maximum isokinetic endurance and electromyographic spectral parameters of the back muscles as a result of wearing a back belt during heavy lifting and lowering. Ciriello V M and Snook, S H J, 20(11) SPINE 1271-1278 (1995). Finish researchers performed a questionnaire based study of 113 patients using lumbar corsets and found that an elastic corset offered the best help for men and a semirigid high braced corset proved better for women. Alaranta H and Hurri H, 20 SCAND J REHAB MED 133-6, 135 (1988).
To test the efficacy of a lumbar corset into which a spinal support made of heat-mouldable plastic was inserted, 19 patients were randomly assigned to wear a corset manufactured by Johnson and Johnson Ltd with or without the plastic insert in the back pocket. By subjective index, the improvement with the support was significantly greater than in those without the support at 4 and 8 weeks. However, objective measurements by goniometer showed no differences in the changes between the two groups. Researchers postulated that the firm lumbar support may restrict motion and prevent the patient from undertaking movements that precipitate pain. Million R, et al, 40 ANN RHEUM DIS 449-454 (1981).
In studies of the effect of a traditional lumbar belt on radiological and goniometric measurements of lumbar and maximal flexion angles, the lumbar belt decreased lumbar lordosis measured in the orthostatic position to 31 degrees (SD, 10 degrees) from 34 (SD, 11 degrees). These changes were related to the subjects"" initial values and the greatest decreases occurred in subjects with the largest initial lumbar curves (R=0.72, p less than 0.01). In continuous recording tests the changes were similar to those in the single tests. Maximal lordosis angle decreased significantly to 30 degrees (SD, 10 degrees) from 36 degrees (SD, 10 degrees), and mean lordosis angle decreased significantly from 21 degrees (SD 11) to 17 degrees (SD 9) but the decrease in maximal flexion angle was not significant. Thoumi P, supra, at 21.
Scientific literature includes conflicting reports and more work is needed in this area. None of the previously known corsets provides for a contractile anterior to posterior contractile force exerted from the sides of body to the back at waist level.
There is a need for a lumbosacral corset that will maintain and increase lumbar lordosis. The inventor, an orthopaedic surgeon, intensely studied the possibility of developing a corset capable of shortening a number of days of treatment. This inventor found that the treatment effect was accelerated when lumbar lordosis was maintained and increased by applying anterior to posterior traction force from the sides of the body to the back at the waist.
One object of this invention is to provide a means to create a contractile anterior to posterior force, specifically a belt-like extensile corset comprising two longitudinally expandable front and back belt members each having an inner and outer surface; means to attach said belt members to each other at their longitudinal centers; means for attaching the longitudinal ends of the front belt member; two direction changing means for said back belt member located on the outer surface of the front belt member positioned so as to be present on the left and right sides when worn; and means for attaching the longitudinal ends of the back belt member to the posterior outer surface of the back belt member lateral to its longitudinal center.
Another object of the invention is to provide a corset capable of shortening the number of days of treatment. The corset is convenient for a patient since health insurance is applied to it in a hospital and there has been a desire to develop a corset having a superior treatment effect, that is, capable of shortening the number of days of treatment.
Methods for treating lower back pain are also provided. In a preferred embodiment of the invention, lower back pain in subacute. In another preferred embodiment, it is muscular low back pain. In a most preferred embodiment, the patient is a woman without central obesity.